Patent GB-804677-A (GB)
Title: Improvements in work-handling mechanism for lathes and other machine tools
IPC: B25J5/04
Filed: 1956-12-03
Abstract: 804,677. Machine-tool details; turning. SENECA FALLS MACHINE CO. Dec. 3, 1956 [Oct. 9, 1956], No. 36914/56. Class 83 (3). Work-handling mechanism for a lathe or other machine-tool comprises a carriage with unloading and loading-units and means to reciprocate the carriage between a machine-loading-position and a replenishing-position, including a pair of spaced grippers on the loading-unit, means to close the grippers on a workpiece, means to move the grippers and workpiece in a straight path inclined downwardly towards the head end of the machine-tool, the workpiece being held horizontally, and means to shift the lowered workpiece axially to its driving-position. A work-handling-carriage 24, Fig. 1, is supported for travelling-movement along an overhead beam 27 which is carried on a bracket 30 over the machine-headstock 20 and a rear pillar 31. The carriage is moved to the two end-positions, shown in solid and broken-lines, by a chain 45, Fig. 2, which carries a pin 52 engaging a block slidable vertically in a guide 54 in a member 55 secured to the carriage. The chain is continusouly-rotated in one direction when a driving-shaft 37 is rotating, and the simulated crank-and-slider mechanism produces the required dwell of the carriage at the end positions. The shaft 37, Figs. 6 and 7, is driven from the motor M through belt-gear and a clutch 91, 92, which drives a shaft 73 and worm 100. The rear end of the shaft 73 carries a brake 82, 83, and an air-operated-piston 72 which operates the clutch and brake simultaneously. The worm 100 drives a wormwheel 101 which has a spring-loaded dog-clutch drive to a member 104, Fig. 7, splined to the shaft 37. A similar drive is provided for a shaft 111 parallel to the shaft 37, the latter driving a shaft 170, Fig. 1, for rotating a cam in the tailstock 21 to feed the spindle thereof (see below). A cam-shaft 116, Fig. 7, driven by gearing from the shaft 111, operates limit-switches 118, to control the machine and work-handling mechanism. Work-gripping mechanism.-The carriage 24 is of V-shape in section, Fig. 10, and has a centrally-disposed cam-drum 120 rotated from the splined shaft 111. A gripper-frame 134, 140, Fig. 12, is arranged on the front of the carriage 24 and is adapted to slide in cylindrical guides 135 for movement in an inclined direction relative to the machine-axis, but with the part 140 horizontal. The frame is moved into loading-position and away therefrom by a crank-arm 130 engaging a slot 132. The crank is moved by the cam-drum 120, Fig. 10, engaging a roller 124 secured to a rack-bar 126 which rotates a pinion 128 fastened to the end of the crank-arm spindle. A similar gripper-frame for unloading is carried at the back of the carriage 24 and is also operated by the cam-track in the drum 120. The rack-gripper-frame carries a pair of gripping members, comprising jaws 141 and a contact-stud which closes the jaws on engaging a workpiece. The loading-jaws are released by movement of the work to the left, Fig. 12, when a flange thereon trips a latch 161. In the case of the rear unloading-grippers a trip is released, in the withdrawn position of the carriage, by mechanism associated with the - finished work-receiving-device (not shown). Tailstocks.-The driving-shaft 170 (see above), is coupled to a shaft 174, Fig. 18, in the tailstock housing 21, and a pinion 175 on the latter shaft drives a toothed wheel 176 connected to a sleeve 178 carrying a cam-drum 181. A roller 182 secured to a sleeve 185 engages the camgroove in the drum 181. The sleeve 185 is slidable over the tailstock quill 187, and has a spring-buffer-connection with the quill at one end so that the quill may have a limited movement to the right under spring-pressure. An air piston and cylinder device may be added to the buffer to give additional pressure to the centre while machining. The quill 187 is provided at the forward end with a live-centre 195. Headstock spindle and work-driver.-At the headstock end, the work is provided with a forged recess into which driving-lugs 210, Fig. 22, engage. These lugs extend from a spring- pressed collar 233, supported by a cap 230, Fig. 21, secured to the machine-spindle 214. Torque is transmitted from the cap 230 to the collar 233 through slots 237 in the former engaging lugs 238 on the rear-face of the latter. The headstock-centre 220, Fig. 22, is slidable in a bush 242 and is connected by a rod 216 to a piston in a low-pressure air-cylinder 211. When a workpiece is placed between the head and tailcentres, and tailstock pressure is applied, this will overcome the low pressure in cylinder 211 and force the head-centre against an adjustablestop 221, when the driving-lugs 210 register correctly. Air-pressure to the cylinder 211, is reversed, to withdraw the centre 220, when a workpiece is being moved to or from working position in the lathe &c.